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Filter Inductor Ferrite Material

Jun 21, 2017

Filter Inductor Ferrite material

Filter inductors are generally ferrite materials, it can be easily combined with the heart through the capacitor to form a composite filter, in the high-performance filter, also uses wirewound inductors. It should be noted that the ferrite material in the high current will occur under the magnetic saturation, reducing filter performance.

Filter inductor design editor

In the full-bridge inverter, the output filter inductance is a key component, and the network system to the output side of the inverter to achieve the power factor of 1, the waveform is sine wave, the output current and network voltage the same frequency. Thus, the appropriate selection of the inductance value directly affects the performance of the circuit. The selection of the inductance value can be considered from the following two aspects:

So we can get the following formula:

In summary, the filter inductance range of values. In the actual design process, due to the inductance of the volume, cost and other factors, generally only need to consider the lower limit of the inductance, that is, slightly larger than the next can be. In addition to the need to point out that the above calculation is based on the rated output voltage, that is, on the basis of taking into account the actual situation of the fluctuation range of network pressure, in the design of the final inductance inductance, inductance rated current.

Which is the average power injected into the grid, is the angular frequency, is the time.

Therefore, the intermediate DC side voltage has a small pulsation, while the output current of the PV array of the aforementioned Boost is superimposed on a high frequency component above the DC. Simultaneous lightning strikes such as spikes and some additional factors can cause fluctuations in the inverter. It is necessary to set the input capacitance so that it distributes a low-pass filter with the distributed inductance on the conductor between the PV array and the inverter so that the interference generated by each part does not affect the other part as much as possible.

From the experience value available: the value of the input capacitor is generally taken.

Taking into account the pressure, we select two electrolytic capacitors in series. As the series of capacitors involved in the equalization of the problem, the use of parallel pressure resistance measures. The use of each parallel capacitor in parallel with a resistor, composed of three resistors in series.

5.3.3 Power factor (PF)

When the inverter output is greater than 20% of its rated output, the average power factor should be not less than 0.85 (lead or lag), when the inverter output is greater than 50% of its rated output, the average power factor should not be less than 0.95 Or lag).